Optical transceivers can be defined through multi-source agreements (MSAs) or equivalents. MSAs are agreements for specifications of optical transceivers agreed to by multiple vendors, organizations, etc. and promulgated for other vendors and network operators to utilize. MSAs allow other vendors to design transceivers to the same specifications reducing risk for vendors and operators, increasing flexibility, and accelerating the introduction of new technology. Exemplary MSAs include XFP, XPAK, XENPAK, X2, XFP-E, SFP, SFP+, and 300-pin. Exemplary MSAs for 40G and 100G include CFP and variants thereof (e.g., future CFP2, CDFP, CXP), OIF-MSA-100GLH-EM-01.0—Multisource Agreement for 100G Long-Haul DWDM Transmission Module—Electromechanical (June 2010) (hereinafter MSA-100GLH), CCRx (Compact Coherent Receiver), Quad Small Form-factor Pluggable (QSFP) and variants thereof (e.g., future QSFP+, QSFP2), 10×10 MSA, and the like. Additionally, new MSAs are emerging to address new services, applications, and advanced technology. Each MSA defines the transceiver's mechanical characteristics, management interfaces, electrical characteristics, optical characteristics, and thermal requirements. Because of MSA specifications, MSA-compliant optical transceivers are standardized among equipment vendors and network operators to support multiple sources for optical transceivers and interoperability. As such, MSA-compliant optical transceivers have become the dominant form of optical transmitters and receivers in the industry finding widespread acceptance over proprietary implementations.
Advantageously, MSA-compliant optical transceivers ensure engineering re-use and compatibility between various applications and the physical media dependent (PMD) transceivers. Further, equipment vendors realize streamlined manufacturing and inventory control by removing wavelength specific decisions from the manufacturing process. For example, all line cards are manufactured the same, and the optical transceiver module with the desired wavelength (e.g. 850 nm, 1310 nm, 1550 nm, coarse wave division multiplexed (CWDM), dense wave division multiplexed (DWDM), etc.) is plugged in as a function of the specific application or development configuration. Network operators and service providers have adopted optical transceivers to reduce sparing costs. Further, significant cost reductions are realized by MSA standardization of optical transceivers because of multiple independent manufacturing sources. The MSA specifications tightly define the mechanical characteristics, management interfaces, electrical characteristics, optical characteristics, and thermal requirements of optical transceivers. Advantageously, this enables interoperability among equipment vendors of optical transceivers, i.e. any MSA-compatible optical transceiver can be used in any host system designed to the MSA specification; however, these tightly defined characteristics limit the performance of optical transceivers since the MSA specifications were designed to maximize density and minimize cost, and not to provide advanced optical performance or other integrated functions.
Due to the low-cost, high-density, and widespread deployment of optical transceivers, both equipment vendors and network operators recognize a need to extend the benefits of optical transceivers to metro, regional and core network applications to enable carrier-grade wavelength division multiplexed (WDM) transport without the need for additional equipment such as optical transponders or additional circuitry performance enhancements. Such a need also must preserve the MSA mechanical characteristics, management interfaces, electrical characteristics, optical characteristics, and thermal requirements to maintain interoperability with existing host systems.
XFP is defined by the SFF Committee, such as in INF-8077i “10 Gigabit Small Form Factor Pluggable Module” Revision 4.5 (Aug. 31, 2005), the contents of which are incorporated by reference herein. XFP is a popular MSA-defined pluggable transceiver used in a variety of applications such as routers, switches, cross-connects, etc. XFP includes various types based on distances up to 80 km. Disadvantageously, XFP only supports distances up to 80 km and does not support integration of FEC, framing, and advanced OAM&P functionality.